Earthquakes and Volcanoes 



in the Mediterranean, between Sicily and the 

 coast of Africa, where there had previously been 

 more than one hundred fathoms of water. The 

 pile of volcanic matter forming this isle must 

 have been upwards of eight hundred feet high, 

 for the highest part of the island was two hundred 

 feet above water; while the circumference of the 

 mass of land was nearly three miles. After it 



Fig. 57. Graham Island, 1831 



had stood above the waves for about three 

 months, the island entirely disappeared. 



It is probable that a great deal of the force 

 by which volcanic products are brought to the 

 surface is due to the conversion into steam of 

 water which, in some way or other, obtains 

 access to the deep-seated molten rocks; but, 

 whether this is the sole source of volcanic energy 

 or not, is uncertain. Numerous hypotheses 

 have been advanced to explain the source and 

 origin of the molten matter itself. Some of 

 these attempts at explanation refer the heat to 

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